citric acid has an acid dissociation constant of 8.4 x 10^-4 it would be most effective for preparation of a buffer with a pH of (A) 2 (B) 3 (C) 4 (D) 5

Citric acid has an acid dissociation constant (Ka) of 8.4 × 10⁻⁴. When it forms a buffer with its conjugate base (citrate), we can calculate the pH using the Henderson-Hasselbalch's equation.

[tex]pH=pKa+log\frac{[base]}{[acid]}[/tex]

The optimum range of pH is pKa ± 1. The pKa is -log Ka = -log (8.4 × 10⁻⁴) = 3.1. The buffer would be more effective for pH between 2.1 and 4.1, especially around 3.1. So the best choice is (B) 3.

okpalawalter8 okpalawalter8 · Answer 2 · 2022-03-25T13:23:47+01:00

The pH level where it will be most effective is mathematically given as

pH= 3

What is the pH level where it will be most effective for the preparation of a buffer?

Question Parameters:

Citric acid has an acid dissociation constant of 8.4 x 10^-4

Generally, the equation for the pH value is mathematically given as

[tex]pH=pKa+log\frac{[base]}{[acid]}[/tex]

Therefore

The Henderson-Hasselbalch equation as written above is used for the calculation of its pH value

In conclusion

pKa=-log Ka

pKa = -log (8.4 × 106{-4})

pKa= 3.1.